In a computer network handling highly confidential data, such as data in military or financial environments, portions of the network may be connected by one-way data links. For example, confidential data that must not be accessed from external sites may be stored on a computer that is configured to receive data over a one-way link and has no physical outgoing link over which data might be transmitted to the external site.
One-way links may be implemented, for example, using Waterfall™ systems, which were manufactured by GITA Technologies, Ltd., and are now manufactured by Waterfall Security Solutions Ltd. (Rosh HaAyin, Israel). When a transmitting computer is connected by a Waterfall system or other one-way link to a receiving computer, the receiving computer can receive data from the transmitting computer but has no means of sending any return communications to the transmitting computer.